Impact evaluation: the experience of the Independent Evaluation Group of the World Bank

Impact evaluation provides a measure of aid effectiveness, that is how good development aid is at reducing poverty. Critics of aid argue that there have been few attempts to measure its impact. This may have been true in the past, but there is a growing body of literature on impact evaluation. This paper reviews the methodological and practical issues in conducting such studies, drawing on the experience of the Independent Evaluation Group of the World Bank.